Capacitors are devices that store electrical energy on a dielectric material between two conductive electrodes, usually metal. Their architecture has followed a path that started as a metal sleeve on the outside and inside of a glass jar (called a Leyden Jar). Today, materials with very high dielectric constants are used in geometries that maximize the area of the electrodes while at the same time providing dielectric thicknesses that result in high breakdown voltages. The combination of high dielectric constant, high voltage, and high electrode surface area leads to an energy storage capability with very high specific energy (energy per unit volume).
Capacitors using dielectrics having very high dielectric constants (values near 20,000 or more) would prove useful in commercial and residential applications. One problem has been the fact that many high constant dielectric materials have a breakdown voltage which can severely limit the maximum allowed applied voltage to the device and thereby limit the amount of energy storage, limiting the utility of the resulting device.